Frame Transmission in DAR Mode

In DAR mode, all transmissions are automatically cancelled after they start on the CAN bus. A Tx Buffer’s Tx Request Pending bit TXBRP.TRPx is reset after successful transmission, when a transmission has not yet been started at the point of cancellation, has been aborted due to lost arbitration, or when an error occurred during frame transmission.

• Successful transmission:

  • Corresponding Tx Buffer Transmission Occurred bit MCAN_TXBTO.TOx set

  • Corresponding Tx Buffer Cancellation Finished bit MCAN_TXBCF.CFx not set
• Successful transmission in spite of cancellation:

  • Corresponding Tx Buffer Transmission Occurred bit MCAN_TXBTO.TOx set

  • Corresponding Tx Buffer Cancellation Finished bit MCAN_TXBCF.CFx set
• Arbitration lost or frame transmission disturbed:

  • Corresponding Tx Buffer Transmission Occurred bit MCAN_TXBTO.TOx not set
  • Corresponding Tx Buffer Cancellation Finished bit MCAN_TXBCF.CFx set

In case of a successful frame transmission, and if storage of Tx events is enabled, a Tx Event FIFO element is written with Event Type ET = “10” (transmission in spite of cancellation).